The present invention is related to an apparatus for removing residues, in particular plastic residues, from parts of plastics processing machines.
A cleaning apparatus of this type is disclosed in the German patent DE-PS No. 31 46 478 and includes a treatment vessel which contains a heat transfer fluid and cooperates with a heating unit. The parts to be cleaned are inserted into the vessel with the fluid heated up to a temperature above the melting point of the adhering plastic residues to be removed. Attached to the container is an electromagnetic vibration exciter which oscillates a disk immersed in the heat transfer fluid.
Since the vessel is sealed off in airtight manner, safety concerns require the cleaning apparatus of this type to be equipped with a pressure control valve which i.e. is responsive when the fluid level of the heat transfer fluid within the vessel is too low so that during heating the pressure of the thus entrapped large air volume exceeds a given limiting value. The pressure control valve is also responsive when the temperature is set to a value above the temperature of decomposition of the respective plastic material. In each case, an actuation of the pressure control valve releases undesired vapor or gases into the atmosphere which may be harmful or at least result in obnoxious odor. Further, in case that materials other than the parts to be cleaned are unintentionally introduced into the vessel the presence of obnoxious gases is encountered when these materials decompose during the heating action. Finally, the vessel may be unintentionally filled with an excessive quantity of heat transfer fluid up to its upper rim so that during the heating step, a certain amount of heat transfer fluid is released via the safety valve into the environment. This, however, leads again at least to obnoxious odor.